1. Field of the Invention
This invention relates to a battery-cover lock mechanism for a portable terminal equipment, such as an electronic pocketbook, in which a backup battery is used in addition to an operating battery.
2. Description of the Related Art
Various battery-cover lock mechanisms of the described type have recently been increasingly put into practice especially for use in portable terminal apparatuses or equipment (hereinafter also called the portable terminal), such as electronic pocketbooks, in an effort to prevent backup data from disappearing in error during exchanging of the operating battery.
This conventional art is exemplified by Japanese Patent Laid-Open Publication No. Hei 7-7278. The conventional locking technology disclosed in this Japanese publication is shown in FIG. 9 of the accompanying drawings of the present invention. As shown in FIG. 9, an operating-battery closure 22, a backup-battery closure 23 and a sliding knob or button 24 are supported on the rear or bottom surface of a lower case or housing 21 as of a portable terminal. The operating- and backup-battery closures 22, 23 each have a non-illustrated engaging portion; the button 24 is slidable, in response to manipulation of the user's finger, on the bottom surface of the lower housing 21 linearly in opposite directions of arrows E, F between a first locking position (left in FIG. 9) where a non-illustrated locking lever (presumably fixed to or integral with the button 24) comes into locking engagement with the engaging portion of the operating-battery closure 22 only and a second locking position (right in FIG. 9) where the locking lever comes into locking engagement with the engaging portion of the backup-battery closure 23 only. Thus as the knob is moved selectively in either direction, only a selective one of the two closures is locked.
However, having a string of two locking positions arranged along a mere straight line, it is difficult to adjustably slide the button 24 to a proper selected position to meet the situation. Yet in the absence of the user's careful attention during battery exchange, it is highly likely that an intended closure or closures would fail to be locked or would be locked incorrectly.